Cushioning device for reciprocating sieves and other apparatus



Oct. 27, 1931. cou 1,829,340

" CUSHIONING DEVICE FOR RECIPROCATI-NG SIEVES AND OTHER APPARATUS Filed May 11 1928 2 Sheets-Sheet 1 Oct. 27, 1931. J, comm 1,829,340

CUSHIONING DEVICE FOR RECIPROCATING SIEVES AND OTHER APPARATUS Filed May 11, 1928 2 Sheets-Sheet 2 Patented Oct. 27, 1931 V STATES;

PATENT orrice V JEANGQUTIN, 0F NOGENT-SUR-MARNE, FRANCE, ASSIGNQR TO PREPARATION 'I'N- DUSTRI'ELLE DES COMBUSTIBLES (SOGIETE"ANQNYME), OF NOGENT'lT-SUR-MARNE,

Cil

CUSHIONING. nnvicn Eon RECIBRQGATING srnvns AND OTHER arrana'rus Application filed May 11,1928, Serial No. 277,021, and in France May 14, 1927.

The present invention relates to a device for cushioning the forces of inertia of reciprocating sieves and other apparatus and for restoring'a part of the energy accumulated during the cushioning, the device be ing of the type which comprises a piston connected to one of the sieves or other device and moving in a cylinder connected to the other sieve or device, the said cylinder containing a liquid and a gas so as to combine the resistance due tothe compression of the liquid with the elastic force due to the compression ofthe gas.

Devices are known for balancing the forces ofinertia by means of springs. Such devices are subject to the following drawbacksr First, the springs may break.

Second, the instantaneous forces of inertia are absorbed by the springs only at the working speed'of'the apparatus 'andspecial means must be used for starting the apparatus by reason of the considerable resistance offered by thesprings.

evices are also known for balancing the forces of inertia by means of a piston and a cylinder. Some of them use the compression [of gases, but offer several drawbackszjt-hey cannot be provided with any outlet or inlet for'gas; hence a heating or a vacuum results;

as pneumatic apparatus, they do not ofier any safety from the point of view of the resistance; theyare not practicalin the case of apparatus havinga small stroke. Other "devices employ the compression'of a liquid in connection with the compressionof a gas;

in these the cylinders are generally connected together by a'conduit in the cylinder wallin order'to allow' the gas to be driven back: on "one side or the other of thapiston. The

drawbacks of such apparatus are as follows:

First, eddies areproduced between the gas and the liquid by reason of their difference 'of'density'and'of the tendency of the gas to passabove the liquid; p I Second, they 'are not practicalin'the case of apparatus having a small stroke;

"Third, the fccmpression produces heat which, after ashorttime, renders'it impossible touse the apparatus.

The present invention obviates all the strokes.

above mentioned drawbacks. Particularly, the arrangement of the gas space in the cylinder is such that no. eddy or mixture between the gas and liquid may occur. The cylinder is in communication with two chant bers which are connectedtogether by a pipe presenting a large external surface so. as to effect a cooling of the compressed gas. This pipe, or by-pass tube, is provided with a regulating valve. Moreover, the two chambers have a cross section difierent from that of the cylinder, so that during the pistoning movement the fluids have in the chambers a displacement different from that in the cylinder. vantageous in the case where movements of high speed and small amplitude are to be damped, the difference in cross section between the chambers and cylinder permitting much higher air compressions to be obtained than in the case of an ordinary cylinder. Indeed with a small piston stroke, in order to obtain a high compression, the dead space would have to be reduced to too small a value and shocks would occur at the end of the The present arrangement, on the contrary, allows a high compression to be easily obtained so as to effectively oppose the considerable forces due to the high speed,

Finally, the boxes of the sieves or other moving masses may be connected to the cylinder and the piston by ash wood links inorder to eliminate joints.

The appended drawings show by way of example a constructional form of the apparat-us.

Fig. 1 is a side view of the apparatus.

Fig 2 is a section on line 22 of Fig. 3.

Fig. 3 is a plan view of the apparatus.

Fig. 4 is a sectional view of the damping cylinder shown in Fig. 2, but on a larger scale.

Fig. 5 is a similar view of another construction of the said cylinder.

the box 2 is actuated by two links 5 of like lOO ' foo construction which are bolted to the angle pieces 6. The links 3 and 5 are actuated by a crank-shaft 7 driven by a flywheel pulley 8 and mounted in the bearings 9.

The said boxes are caused to ,be displaced in parallel position in the direction ofthe arrows 10 and 11, since they are'supported by V angle pieces land 6 securing them to the.

boxes; the links 3 are bolted to a cross-piece 14 and the links 5 tea cross-piece 15. To this latter is bolted a cylinder 16 which is shown on a large scale in Fig. lQ In the said cylinder is movable a piston 17-, optionally provided with:packing-rings, which piston is secured to the cross-piece 14 by the piston rod 18. The cylinder 16 is extended'to'wards the top at each end by two vertical compres- I '1svery small, but a powerfulmotor would be necessary for starting purposes, unless sionl tubes 19 and 20. The crosssectional area of each of the tubes-19 and 20 is much smaller than the area of piston 17 ,being only about one-tenth of the latter. The said-tubes 19 and 20 when thepiston is middle 'position. Y At the normalispeed of 'the sieve apparatus,

.which is quite considerable, there will be produced great efforts of acceleration at each end of the stroke, which efforts are due to the weight of the boxes inmotion. .The stroke of the piston is very short, but theicylinder 16' is filled with glyoerine andfora short movement of distance of the piston, the glycerine will be displaced-through a distance which. is ten times greater in the vertical tubes19 and 20. If the holes 21 would not be provided, it wouldbe feasible, for 'eX-- of the glycerine in the tubes19 and20, to

ample, by. means of this great displacement compressthe air in the upper parts of said tubes to a high pressure, forexample l5'kgs.-

' per sq. cm. If the top surface ofthe glycerinein 19 .and20 is 15 sq. cm. and the sur-v face of the'pisto'n 17 is 150 sq. cm., the effort .-dueto.t his compression'of the '.air willbe 300 kgs. upon the surface of the glycerine in '19 and20,-and 3000 kgsupon the piston 17; 7

according to Pasoals principle. i gIt isifeasible to employ hole ficiently small size that duringfa compression stroke only a small, amount of air would "have time to escape through'such holes, the ispeed of-the sieve apparatus-being consideT- 1 for damping the effortsv of ins 21- of suf-f able,.as above mentioned. If it is admitted that by the use of said holes the pressure is reduced to 16 kgs. per sq. cm. at the end of the stroke, this will produce an effort of 240: kgs,J.upOn the surface of the glycerine in 19 and 20, and 2400 kgsljon-the piston 17 At each end-of the stroke,.the force produced onone or the other faces of thepiston 17 will oppose the force of inertia, and there-may be obtained a force which is prac tically equal to the force of inertia, thus equilibrating such force of inertia; The actuating links and the crank-shaft are subjected to small. stresses, andv onlya reduced amount of power is necessary to operate the apparatus. c When starting, if the holes 21 were not provided, it would be necessary to'produce V a great eifort in order to. set the sieve-apparatus in action,v since the efforts of inertia": ,due to the boxes are zeroat the start, and will not equilibrate theefiort of air compression in .the tubes 19 and 20. The power required to operate the apparatus at the normal speed special means were used, for instance by increasmg the stroke of the boxes at the same time as the speed. This drawback is obviated 1 by theholes 21. In fact, whenstarting the apparatus, the speed is small and the air will have time to issue through the holes 21. The

pressure of the air at the-end of the stroke in the tubes-19 and 20 increases concurrently with thespe'ed of the sieve, i. ve. at the same time as the'eflorts of inertia togbe overcome. 1 These eflorts will therefore be equilibrated for all speeds of the sieve apparatus.

Theholes21 also afford another advantage; if they were notprovided, the air would thus maintaining the proper temperaturelof the air-.-

Theuse of-the holes 21 affording anatmospheric communication for thecompression tubes 19 and 20 when the latter are notconnected together by means of the tube 26 may' prove a drawback. Since the pressure in the t'ubes19'and 20 attains 16 kgs. .per sq.cm., the

airwi-ll be expelled to theexterior at-a much greater speedthan that with which the air enters the tubes containing a vacuum. The pressure causing this latter being less than atmospheric. pressurfi, a vacuum will be formed above the liquid in thetubes 19 and 20. To. obviate this drawback, the'holes. 21 can be-conneoted byfsuch a tube 216 that the air issuing from the tube 19 will be obliged tov enter the tube 20. -Thesaid tube seniay be provided with a regulating cock'2 7. Itmay be made of brass and may have a large surface in order to cool the' air circulatin'g'from the tube 19 to the tube 20, and inversely. The whole device may also be provided with cooling wings or flanges 28, see Fig. 5.

The said arrangements according to the invention are applicable to sifting apparatus other than what has been described, but the said apparatus is advantageous from the fact that it dispenses with the pivot joints which are subject to wear.

It is also feasible to dispose the crank-shaft or shaft carrying actuating eccentrics, as well as the damping cylinder, in any suitable position.

The apparatus may further comprise a certain number of damping cylinders, and the aforesaid devices may be employed upon oscillating apparatus of all types.

hat 1 claim is:

1. A device for cushioning the forces of inertia of reciprocating masses and for restoring a part of the energy accumulated during the cushioning, said device comprising a piston connected to one of the masses and a cylinder connected to the other mass, said piston moving in said cylinder, two vertical tubes extending respectively from the ends of the cylinder, said tubes and cylinder inclosing a liquid and a gas, the latter being contained in the upper portions of said tubes, with the levels of separation of the liquid and gas in the same horizontal plane, and a bypass pipe having a large external surface adapted to be cooled connecting said vertical tubes.

2. The combination set forth in claim 1 in which said by-pass pipe is provided with a regulating valve.

3. The combination set forth in claim 1 in which said vertical tubes have a cross section different from that of said cylinder, the arrangement being such that the fluid in said tubes has a path of flow different from that of said piston.

In testimony whereof I hereunto afiix my signature.

JEAN COUTIN. 

